The present invention relates to a vehicle airbag apparatus.
Vehicles such as automobiles are generally provided with an airbag apparatus for protecting an occupant seated in a vehicle seat from an impact of, for example, a vehicle collision. Airbag apparatuses have been proposed that, for example, inflate and deploy an airbag provided in the vehicle seat between an occupant seated in the seat and a body side portion of the vehicle by supplying inflation gas into the airbag.
In such airbag apparatuses, the airbag is partitioned into a plurality of expansion chambers in practical use. For example, in the apparatus disclosed in Japanese Laid-Open Patent Publication No. 2011-126413, the airbag is partitioned into two expansion chambers in a longitudinal direction. When the airbag is deployed and inflated, inflation gas is discharged from a gas supply port of an inflator toward the inside of the expansion chambers.
Typical airbags are formed into a bag shape by joining the periphery of a base fabric sheet that is folded in half or by joining the periphery of two base fabric sheets overlapped with each other by, for example, sewing or adhesion. When the airbag is deployed and inflated, the internal pressure of the airbag acts to separate the joint portion of the base fabric sheet. Thus, the joint portion of the base fabric sheet is required to have high bonding strength.
In the above-mentioned apparatus, when the airbag is deployed and inflated, the inflation gas is discharged toward the inside of the expansion chambers. Thus, the inflation gas reaches and is sprayed to the periphery of the base fabric sheet, that is, the joint portion via the inside of the expansion chambers. Since the inflation gas is highly pressurized, great stress is generated on the joint portion to which the inflation gas is sprayed. Generation of great stress is not preferable in further improving the reliability of the airbag.